Former undisputed middleweight champion Marvin Hagler has died aged 66.

Hagler died unexpectedly at his home on Saturday, his wife, Kay, announced on Facebook.

"I am sorry to make a very sad announcement. Today, unfortunately my beloved husband Marvelous Marvin passed away unexpectedly at his home here in New Hampshire," a statement posted on his official fan page read.

"Our family requests that you respect our privacy during this difficult time. With love."

Hagler was the undisputed middleweight champion between 1980 and 1987, cementing his place as one of the greatest boxers of all-time.

The American finished his professional career, which ended in 1987, with a 62-3-2 record.

His victory over Thomas Hearns in 1985, which became known as 'The War', is remembered as the most famous fight of his career.

Hagler was inducted into the International Boxing Hall of Fame in 1993.